Influence of High-Frequency High-Voltage Impulse Conditioning on Back-to-Back Capacitor Bank Switching Performance of Vacuum Interrupters

The objective of this paper is to investigate an influence of high-frequency high-voltage impulse conditioning on the back-to-back capacitor bank switching performance of vacuum interrupters (VIs). Nine identical 7.2-kV VIs were tested by 80 CO operations after the proposed conditioning. Test inrush currents were set to 0-, 2-, and 5-kA peak. The experimental results showed that this conditioning technology could make an impact on both prestrike and restrike characteristics of VIs. The complementary cumulative distribution function (CCDF) of the prestrike gap dpre followed complementary Weibull distribution. In contrast to VIs without conditioning, three typical prestrike gaps, i.e., CCDF 10% prestrike gap d
_1̅0̅
CCDF 50% prestrike gap d
_5̅0̅
, and CCDF 90% prestrike gap d
_9̅0̅
, decreased by 39%, 19%, and 4% at most, respectively. Besides, the scattering of dpre decreased by 52% at most. Furthermore, the conditioning technology had an influence on the feature of restrike waveform through variation of field emission current. It could also reduce the restrike probability by 22.5% at most and made the entire restrikes occur between 0.5T and 5T during recovery voltage period (T = 20 ms).